Biomass
Burning plants for electricity. Genuinely carbon-neutral in some forms, and a catastrophe dressed as a solution in others. The difference is entirely in the feedstock, and the industry has abused that ambiguity.
The effect compounds within years. Put it in place and it keeps working.
Origins
Burning plants is the oldest energy technology there is. It is what fire is.
For most of human history, biomass was energy: wood for heat, charcoal for smelting, dung where there were no trees. It is still the primary cooking fuel for around 2.1 billion people. The Industrial Revolution was, in part, a response to the fact that Britain had run out of trees and had to dig for something to burn instead.
Its modern return came with an accounting decision, and the accounting decision is where all the trouble started.
Under international carbon accounting rules, biomass combustion was treated as carbon neutral. The logic was that the carbon released came from a plant that had recently absorbed it, and a new plant would grow and absorb it again. Emissions were counted in the land use sector where the tree was cut, not in the energy sector where it was burned.
This created an accounting hole large enough to drive a forest through. A power station in Britain could burn wood pellets shipped from American forests and report zero emissions at the smokestack, while the emissions from the cut forest were recorded, if at all, in another country’s ledger.
The Drax power station in Yorkshire, once Europe’s largest coal plant, converted to wood pellets and became, on paper, one of Britain’s largest sources of renewable energy. It burns millions of tonnes of wood a year, much of it from the southern United States, and it has been the subject of sustained investigation and sustained controversy. It is the single clearest example in the world of a climate policy producing an outcome opposite to its intent.
What it actually is
The claim that biomass is carbon neutral rests on a real fact and an unstated assumption, and it is the assumption that fails.
The real fact: the carbon in a plant came from the atmosphere recently, not from underground. Burn it and you return carbon that was already in the fast carbon cycle. Burn coal and you introduce carbon that has been out of that cycle for three hundred million years. These are genuinely different, and that difference matters.
The assumption that fails: that the plant regrows and reabsorbs the carbon, and that this happens fast enough to matter.
For a crop residue, a sawmill offcut, or a fast-growing grass, it does. The carbon is back within a year or two, the material was waste anyway, and the arithmetic works.
For a mature tree, it does not. Burning a tree releases in an afternoon carbon that took eighty years to accumulate, and the replacement seedling needs eighty years to take it back. There is a carbon debt, incurred now and repaid over a human lifetime — and we do not have a human lifetime. Worse, per unit of electricity, burning wood emits more CO₂ at the stack than burning coal, because wood is less energy-dense and wetter. In the near term, when it matters most, converting a coal plant to wood pellets can make emissions worse.
The technology is not the problem. The feedstock is the entire question, and the industry has systematically blurred it.
The numbers
The accounting hole. Biomass combustion has been treated as zero-emission at the point of burning under international rules, with emissions attributed to the land-use sector instead. This is why a power station can burn millions of tonnes of wood and report itself as renewable.
The stack emissions. Per unit of electricity generated, burning wood releases more CO₂ than burning coal, because wood has lower energy density and higher moisture content. This is not disputed. What is disputed is whether the regrowth cancels it, and over what timescale.
The carbon debt. Burning a mature tree incurs a debt repaid only as the replacement grows — decades to a century. Analyses of pellet supply chains have repeatedly found payback periods long enough to be irrelevant to the timeframe in which emissions must fall.
Where it genuinely works. Sawmill residues, crop residues that would otherwise be burned in the field, genuinely surplus material, and fast-rotation energy crops on degraded land, all of which regrow within a year or two. In these cases the carbon neutrality claim holds and the material was waste.
The scale of the confusion. Both of the above are called “biomass” and both are counted the same way in most national statistics, which means the category is close to meaningless without knowing the feedstock.
And the traditional reality. For 2.1 billion people, biomass is not a policy debate. It is the fire they cook on, and it is killing around three million a year through household air pollution.
Why it matters
We want to be careful here, because it would be easy to write this page as a simple denunciation and that would be wrong.
Fire is the oldest human technology and burning plants is not a sin. A wood stove burning offcuts from a local mill, in a house in a forest, is a perfectly reasonable thing and always has been. A power station burning sawdust that would otherwise rot is doing something sensible. The straw left after a harvest, currently burned in the field for nothing, is a genuine energy resource being wasted.
What has happened is not that burning plants became evil. It is that an accounting convention created an incentive to cut down forests and call it renewable energy, and an industry grew up inside that loophole and has defended it with great vigour and considerable money.
That is a policy failure, not a technology failure, and it matters that we say so clearly, because the lesson generalises: a climate rule that measures the wrong thing will be gamed, reliably, by people who are following it. Nobody at Drax is breaking the law. They are doing precisely what the rules reward.
Which is why we keep returning, on this site, to the same point. The forests being cut in the American Southeast to keep the lights on in Yorkshire are not being cut by villains. They are being cut because somebody wrote a rule that said this was clean. The rule was wrong.
Fix the rule, and biomass goes back to being what it always was: a good use for genuine waste, and a terrible reason to cut a tree.
What it actually takes
Fixing the accounting. Everything else follows. Emissions from burning biomass should be counted where they are emitted, with credit given only for carbon that is genuinely and rapidly reabsorbed. The current convention is the root of the problem.
A hierarchy of feedstock, enforced. Sawmill residue: yes. Crop residue: yes. Genuinely surplus material: yes. Whole trees from productive forest: no. Purpose-grown wood for pellets: no. This distinction is not difficult; it is simply inconvenient.
Honesty about timescale. A carbon debt repaid over eighty years is not a solution to a problem defined by the next twenty. This is the single most important argument and it is the one the industry most consistently avoids.
Not letting it displace better options. Biomass electricity is now more expensive than solar and wind, and it competes for the same subsidies and the same grid connections. Money spent on burning wood is money not spent on things that are cheaper and cleaner.
And keeping the traditional-use question separate. The 2.1 billion people cooking on biomass are not part of this policy argument, and their problem — three million deaths a year from household smoke — is far more urgent than any of it.
Where it matters most
The American Southeast is where the wood is coming from. Forests in the coastal plain are cut, pelletised, and shipped across the Atlantic to be burned in European power stations that report themselves as renewable. It is a supply chain that exists purely because of an accounting rule.
The United Kingdom and the Baltic region are where it is being burned, and where the subsidies flow.
The Nordic countries are the honest counter-example: substantial biomass energy drawn genuinely from forestry residues and integrated with a real forest industry, which is roughly the model everyone claims to be following and few are.
The Carpathians have seen illegal logging driven partly by biomass demand, in some of Europe’s last primeval forest.
Sub-Saharan Africa and South Asia are where biomass is not a policy question at all. It is a fire in a kitchen, and the people breathing it are dying at a rate of around three million a year.
How to tell it’s being done well
What is the feedstock? This is the entire question and everything else is noise. Sawmill residue and crop waste: legitimate. Whole trees: not.
What is the carbon payback period? If the answer is decades, it is not a climate solution on any timescale that matters, whatever the accounting says.
Would this material have rotted or been burned anyway? If yes, burning it for energy is a gain. If no, you have created a demand for cutting something down.
Is it displacing coal, or displacing wind? Biomass replacing coal in the short term may be defensible. Biomass taking subsidy and grid capacity that would have gone to solar is not.
What you can do
Anyone
- When you hear biomass energy, always ask what the feedstock is. Sawdust and whole trees are both called biomass and they are not remotely the same thing.
- Per unit of electricity, burning wood emits more CO2 at the stack than burning coal. Whether that is cancelled by regrowth depends entirely on what was burned and how fast it grows back.
Policymakers
- Fix the carbon accounting. Emissions should be counted where they are emitted, with credit only for carbon genuinely and rapidly reabsorbed. This single change would end most of the harm.
- Enforce a feedstock hierarchy. Residues yes, whole trees no. The distinction is easy and it is being deliberately blurred.
- Stop subsidising it against solar and wind, which are cheaper and cleaner and competing for the same money.
Business and investors
- Biomass electricity carries substantial and growing regulatory and reputational risk precisely because the accounting is likely to be corrected.
- Genuine residue-based biomass, integrated with real forestry, is defensible. Pellet supply chains built on whole trees are not, and the exposure is increasing.
Who is working on this
We are researching which organizations in our directory of 8,493 actively work on this solution, and we only list an organization once we have verified it. That research is ongoing. In the meantime, search the directory yourself:
Questions
Is burning biomass carbon neutral?
Sometimes, and the difference is everything. The carbon in a plant came from the air recently, not from underground, which genuinely distinguishes it from coal. But the claim depends on the plant regrowing fast enough to matter. For crop residue or fast-growing grass, it does. For a mature tree, it does not: you release in an afternoon carbon that took eighty years to accumulate, and the replacement needs eighty years to take it back.
Does burning wood really emit more than coal?
Per unit of electricity generated, yes. Wood is less energy-dense and wetter than coal, so more CO2 leaves the stack. This is not disputed. What is disputed is whether regrowth cancels it, and over what timescale, and the timescale is the problem.
How did this become policy?
Through an accounting convention. Biomass combustion was treated as zero-emission at the point of burning, with emissions attributed to the land-use sector where the tree was cut instead. That created a hole large enough to drive a forest through, and an industry grew up inside it. Nobody is breaking the rules. The rules were wrong.
What is the Drax example?
Drax in Yorkshire, once Europe's largest coal plant, converted to burning wood pellets and became on paper one of Britain's largest renewable energy sources. It burns millions of tonnes of wood a year, much of it shipped from the American Southeast. It is the clearest illustration anywhere of a climate policy producing the opposite of its intent.
So is all biomass bad?
No, and it would be wrong to say so. Sawmill residues, crop residues that would otherwise be burned in the field, and genuinely surplus material are legitimate feedstocks. They regrow within a year or two, they were waste anyway, and burning them for energy is a real gain. The technology is not the problem. The feedstock is the entire question.
What about the 2.1 billion people who cook on wood?
That is a completely different question and a far more urgent one. For them biomass is not a policy debate but a fire in a kitchen, and the smoke is killing around three million people a year through household air pollution. It should not be conflated with the power station argument.
Sources
- Project Drawdown - Biomass Power (Drawdown Explorer) Framework and classification. Cited, not reproduced.
- Sterman et al. (2018), Environmental Research Letters - Does replacing coal with wood lower CO2 emissions?
- European Academies Science Advisory Council (EASAC) - Forest bioenergy and carbon neutrality
- IPCC (2022), AR6 Working Group III - Energy Systems and Bioenergy
- Chatham House - Woody Biomass for Power and Heat
The solution taxonomy follows the framework popularised by Project Drawdown. The analysis above is our own; for their carbon modeling and rankings, visit them directly.